Heinrich ohagen



Sept. 25, 1928. 1,685,373

H. OHAGEN MILLING CUTTER FOR- CUTTING SHARPLY POINTED ANGULAR INCISIONSINTO WOOD Filed A ril 14, 1927 Patented Sept. 25, 1928.

UNITED STATES PATENT OFFICE.

HEINRICH OHAGEN, oF BREsLAU, GERMANY.

MILLING- CUTTER FOR CUTTING SHARPLY-POINTED ANGULAR INCISIONS INTO WOOD.

Application filed April 14, 1927, Serial No. 183,740, and in GermanyApril 23, 1926.

This invention relates to a milling cutter for making in wood sharplypointed angular incisions. It has been found that incisions in wood inthe shape of an acute angle cannot be produced with the aid of amilling-cutter, the

= cutter cuts the incision substantially to about half its depth, themiddle-cutter cutting then to about of the depth and the last cuttercutting then the fine point of the incision and giving to the incisionthe final sharp shape. The milling-cutters are so arranged that theyeither move the one directly behind the other, or the milling-cutters ofdifferent size are arranged on a common disk. When this working methodis applied the individual cutters are submitted to such little stress,that no getting hot nor burning of the knives occurs.

in the acccnianying drawing:

Fig. 1 shows in cross section a. piece of wood with an acute-angledincision.

Fig. 2 shows in plan view the piece of wood and the arrangement of themilling cutters for producing the incision, three cutters having knivesof different length and thickness 5 running the one behind the other.

Figs. 9, and 11 show each another form of construction of themilling-cutter in which the roughing knives and the finishing knives areunited in one single cutter, the longer finishing knives beingoscillatably mounted in U the cutter-disk.

As shown in Fig. 2 the three cutters A, B and C are rotatably mounted inthe bearings of a common frame D, the cutter A being driven by thebelt-pulley 1, the cutter B by the belt-pulley 2 and the cutter C by thebelt-pul The knives 6 of the cutter A are shorter than the knives 7 ofthe cutter B and these are again shorter than the knife 8 of the cutterC. The knives 6 reach to about one half of the depth of the incision tobe cut, the knives 7 to about of the depth of the incision, while theknives 8 serve to cut the fine point of the incision.

A special. characteristic feature of the invention consists in theconstruction of the knives 6,7 and 8. The side-faces of the roughingknives 6 and 7 have sharp edged grooves 9, so that these sidefaccs exerta saw-like effeet. The same saw-like shape might be obtained bycomposing. as shown in Figs. 4; and 7 withregard to the knives 7, theknives of three or more elements, each element being of trapezoidalcross section. By this arrangement surfaces acting like saws areproduced on the side-edges of the knife.

The knives 8 of the finishing cutter C are smooth on the sides, theirouter working surfaces are however cut at 10 saw-like so that theside-walls of the incision in the wood and also the point of theincision can be cut easily and cleaning by these saw-like knives. Onlythe finishing knife 8 possesses in longitudinalsection accurately theshape of the incision to be cut into the wood, the knives 7 beingslightly narrower than the knives 8 and the knives 6 being againnarrower than the knives 7, so that the roughing knives cut theside-walls of the incision only roughly. these side-walls being outbetter by the middle knife and the proper shape being given to theside-walls by the finishing knife. All the knives are consequentlysubmitted to the lowest possible stress and any inaccuracies due toeventual giving way of the cutters in lateral direction being avoided sothat, at the end of each cutting operation, a perfect acute angledincision has been obtained.

The milling-cutters shown in Figs. 9 to 11 comprise each two groups ofknives, the knives of the first group being shorter than the knives ofthe 2nd group and designed for the rough-cutting, the longer knives ofthe 2nd group being designed to cut the point of the incision. In thisform of construction the longer knives are arranged, so that they canoscillate in the plane of the millingcutter, i. e. give way in rearwarddirection. Owing to this arrangement the short and the long knivescirculate at the same angular speed, i. e. they may be united in onesingle milling-cutter, the long knives giving way however in rearwarddirection as soon as they cutinto the wood, so that at the cutting ofthe wood they retard their movement with regard to the movement. of thestationary knives and when penetrating into the wood they circulate atfirst with the same circumferential speed as the stationary shortknives. The centrifugal force acting upon the long IllVQEs has thetendency to bring these knives into the upright or radial position.Springs might be arranged to assist the action of the centrifugal forceupon the knives. The knives are no longer forced through the wood, i. c.they do not strike upon the wood with a hard shock, but their cuttingedges are gradually pressed into the wood by the effect of thecentrifugal force, eventually assisted by the action of the springs, sothat their euttingaction begins when penetrating into the wood with thecircumferential speed of the short knives and increases gradually at thecutting through of the wood, so thatconseqnently clear incisions withoutburr are obtained, burning or breaking of the fine points of the longknives being excluded.

In the form of construction shown in Fig. i) the short roughing knives11 are rigid with the cutter-disk 12, the finishing knives 13 beingoscillatably mounted on bolts 14 of the disk. lhese finishing knives 13have each an arm 15 by the mass of which the effect of the cei'itrifugalforce acting upon the knives 13 and having the tendency to bring theseknives into their radial position is increased.

When long knives are used, the centrifugal force of which issufficiently great, the arms 15 may be omitted.

As shown in Fig. 10 blade'springs 16 are arranged which act upon theoscillatable knives 13 and have the tendency to bring the same into theradial position.

According to Fig. 11 a ring-shaped spring 17 common to all knives 13 isarranged onto which bear flattened portions 18 of the knives 13. Theflattened portions 18 terminate in noses 19 by which the ring-shapedspring 17 is compressed as soon as the knives oscillate in rearwarddirection. The ring-shaped spring 17 is thus put under tension, so thatit has the tendency to return the knives 13 into the radial position.

1. A milling-cutter in which the roughing knives and the finishingknives are mounted on one and the same cutter-disk, comprising incombination with the cutter-disk, roughing knives rigid with said disk,and finishing knives mounted in said disk so that they can oscillate inthe plane of said disk.

2. A milling-cutter as claimed in claim 1, in which the oscillatablefinishing knives have each an arm for increasing the effect exerted bythe centrifugal force upon the knives.

3. A milling-cutter as claimed in claim 1, in which blade-springs arearranged in the cutter-disk, one for each oscillatable knife anddesigned to bring said knives into the radial position.

1. A milling-cutter as claimed in claim 1, in which a ring-shapedspring, common to all oscillatable knives, is arranged in thecutterdisk, each roughing knife having a flattened portion designed topress upon said ringshaped spring. 1

In testimony whereof I affix my signature.

HEINRICH OHAGEN.

